Fuzz pedals, especially vintage ones and retro designs tend to have a very low input impedance which naturally rolls off a lot of high end from your guitar. So the loading down effect which is what the buffer+ is designed to counter, actually contributes to the way certain fuzz pedals are meant to sound. So worst case scenario, your fuzz will sound a lot brighter than it otherwise would without the buffer in front. Our fuzz and germ pedals have a higher input impedance so there's no audible difference before or after. But as always, experiment and see what works for you!